The present invention relates to a shock prevention apparatus and method for hydraulic/air-pressure equipment such as construction equipment including excavators, loaders, bulldozers and cranes, which use hydraulic/air-pressure cylinders and motors as actuators.
In general, construction equipment such as excavators, loaders, bulldozers and cranes used at construction sites, are equipment performing mechanical works using hydraulic/air-pressure force. Such construction equipment may cause shocks due to the abrupt opening and closing of oil/air passages when the hydraulic actuator starts or stops quickly. The shocks would unavoidably lower the durability and reduce the expected life span of the construction equipment.
Further, these shocks are delivered to the equipment's body and cause violent vibrations, thus reducing the work efficiency of the driver.
Conventionally, in order to prevent or reduce the severity of the shock, a shockless valve or an orifice is employed in the hydraulic/air-pressure circuits. However, it is known that the effect of this shockless valve or the orifice is insufficient, and the design and the control thereof are troublesome.
In addition, in order to prevent the shocks at the stroke ends of the piston of the actuator (for example, a hydraulic cylinder), a mechanical cushion device has been installed at the ends of the piston of the hydraulic cylinder. However, there was a problem in that precision mechanical manufacturing was demanded and that the device could become damaged or destroyed due to the friction or the shocks of the cushion device itself.
Accordingly, there is a strong demand for an effective and essential solution for preventing shock in hydraulic/air-pressure equipment.